Fluid applicator



1966 D. B. MOINTYRE ETAL 3,294,050

FLUID APPLICATOR Original Filed April 20, 1963 INVENTORS DONALD B. M;INTYRE FREDERIC S. Mc INTYRE ATTORNEYS United States Patent 3,294,060FLUID APPLICATOR Donald B. McIntyre, 210 Hillside Ave., Needham, Mass.

02192, and Frederic S. McIntyre, 19 Garrison Road,

Wellesley, Mass. 02181 Continuation of application Ser. No. 281,623,Apr. 20,

1963. This application Mar. 21, 1966, Ser. No. 536,152 4. Claims. (Cl.118-461) This is a continuation of application Serial No. 281,623 filedApril 20, 1963 and now abandoned.

The present invention relates to fluid applicators, and, morespecifically, to systems for applying predetermined patterns of adhesivemelts and similar fluids to web surfaces and the like.

While wheel-type adhesive and similar fluid dispensers have beenemployed for many decades, the construction of such applicators hasrequired a relatively fixed position of operation thereof to preventfluid leakage and thus has inherently seriously restricted the possibleorientations or directions of travel of surfaces, such as paper webs orthe like, that are to be coated with fluid from the applicators ordispensers. In addition, the thickness of fluid applied has oftenvaried.

An object of the present invention, accordingly, is to provide a new andimproved fluid applicator that is not subject to these disadvantages,but that, to the contrary, is orientable in many different positions andis adapted for coating paper webs or the like that are traveling alongwidely different directions.

A further object is to provide a novel fluid applicator that, whileparticularly useful for the coating of adhesive melts at predeterminedregions, is of more general utility, also; it being understood that thesubsequent description of the invention in terms of the preferredadhesive-coating application is but illustrative of the many differentkinds of fluid-application systems that may advantageously use the novelconstruction of the invention.

Another object of the present invention is to provide a novel fluidapplicator which may be used to apply a thin, highly uniform coating offluid to a paper web or the like, or which may be used to apply suchfluid to predetermined regions only of the web.

Other and further objects will be explained hereinafter and will be moreparticularly pointed out in connection with the appended claims, theinvention now being described in connection with the accompanyingdrawing, FIG. 1 of which is a longitudinal section of a preferredembodiment; and

FIG. 2 is a fragmentary similar view of a modification.

A fluid-applicator wheel 1, as of metal or the like, is shown containinga plurality of peripheral fluid-receiving gravure-like depressions 3distributed about the circumference of the wheel in accordance with apredetermined pattern corresponding to predetermined spaced regionsalong a sheet-material web 5, illustrated as horizontally tangentiallycontacting the wheel at its uppermost point. As later pointed out, wherea continuous coating is desired, the depressions 3 may be omitted. Theweb 5 is driven in the direction of the arrow as by drive rolls 7, thespeed of which may be synchronously adjusted, by conventional means,with respect to the rotating shaft 9 of the wheel 1 (indicated by theschematic synchronizing connection 11), to insure that the successivefluidfilled depressions 3 contact the successive predetermined regionsof the web 5 to coat such regions with fluid.

The wheel 1 rotates through-a cavity 2 in a block 2', with successiveperipheral portions of the wheel receiving fluid introduced into thecavity 2 at an inlet 4. In the preferred hot-melt adhesive application,the inlet 4 communicates by a conduit, schematically shown at 6, with aheated adhesive-melt reservoir 17. Gravity or pressure inlet feed may beemployed.

3,294,060 Patented Dec. 27, 1966 A doctor blade 8 is disposed adjacentthe wheel 1 at the right-hand end of the cavity 2 a predetermined smalldistance from the said wheel in a recess near the region at whichsuccessive peripheral portions of the wheel emerge from the cavity 2during rotation thereof. The doctor blade 8 is adjustable toward or awayfrom the wheel by a set screw 10. A cutter edge or projection 8",substantially tangential to the wheel 1, serves to slice the fluidcarried between the cavity 2 and the smooth surface 3' of the wheel 1.At or near the region of the edge or projection 8", the speed ofrotation of the wheel 1 and of the fluid approximate to each other sothat the fluid is not substantially impeded by the presence of thedoctor blade 8, but is actually sliced at 8" and set into a vortex spin,rotating clockwise within the substantially circular duct 8 andreturning to the wheel periphery ahead of or preceding the cutter edgeor projection 8". This serves to break surface tension by thedifferential velocity created by the vortex and insures complete fluidfilling of the depressions 3; or, in the absence of depressions 3, auniform coating or layer of predetermined thinness along the smoothsurface 3 of the wheel 1. The cutter edge 8" is shown preferablyextending rearwardly into the upper end of the duct 8, which, as shown,has a cross-section extending progressively farther away from theperiphery of the wheel and then progressively closer to the periphery ofthe wheel. It has also been found appropriate, in some applications,resiliently to urge the doctor blade 8 against the wheel, as by a spring18, FIG. 2, in which event substantially the only fluid remaining on theperiphery 3 of the wheel 1 after it passes the doctor blade 8 is thefluid received within the depressions 3. Unlike prior-art doctor-bladesystems, moreover, the construction 888" forces the doctor blade in thedirection toward the wheel 1 instead of away therefrom. While suchprior-art blades can be used for speeds up to about 350 feet per minutebefore voids appear in the coating of the wheel, speeds of over 700 feetper minute, without voids, have been attained with the presentinvention.

By limiting the transverse width of the cavity 2 to just slightlygreater than the width of the wheel 1, and providing an overflow outlet12 near the left-hand end of the cavity 2, negligible adhesive-meltleakage is produced. When the outlet 12 is connected, as at 14, back tothe reservoir 17, a complete closed-loop system is provided that hasbeen found, in practice, to operate with the system 1-2' orientedthrough a wide range of angular positions of mounting. By making thediameter of the wheel 1 greater than the length (horizontal) of thecavity 2 and block 2, moreover, the web 5 may tangentially contact thewheel 1 from the vertical direction 5' (on either side of the wheel 1)to the horizontal direction at 5, thus removing restrictions on thedirection of web travel. Excess fluid built up to the left of the doctorblade 8 may be removed through a pressure-relief channel 16communicating with the inlet 4.

Clearly, a pair of oppositely constructed systems 1-2' may be used forsuch purposes as providing spaced parallel adhesive coatings for bookedges or the like; and other arrangements of pluralities of such systemsmay also be employed.

Further modifications will also occur to those skilled in the art andall such are considered to fall within the spirit and scope of theinvention as defined in the appended claims.

What is claimed is:

1. A fluid-applicator system having, in combination, a wheel forreceiving fluid along the peripheral surface thereof, means for rotatingthe wheel to contact surfacesto-be-coated by the fluid, a block housinga fluid-containing cavity through which the successive peripheralportions of the wheel may pass during rotation of the wheel, and adoctor blade supported by the block and disposed adjacent the wheelsubstantially at the end of the cavity from which the successiveperipheral surface portions of the wheel emerge during the saidrotation, the doctor blade having a cutter edge oriented to slice thefluid carried thereto to a predetermined thickness, the blade having aduct preceding the cutter edge to receive the sliced fluid andre-deliver the same to the wheel peripheral surface ahead of the cutteredge, said blade being supported on said block for movement toward andaway from the periphery of said wheel, said cutter edge having aprojection extending substantially tangential to said wheel at said endof the cavity and extending rearwardly a predetermined distance intosaid duct, said duct having a substantially circular cross-section whichextends from said edge progressively farther away from the periphery ofsaid wheel and then progressively closer to the periphery of said wheel.

2. A fluid-applicator system as claimed in claim 1 and in which thewheel is provided with fluid-receiving gravure-like depression means.

3. A fluid-applicator system as claimed in claim 1 and in which means isprovided for resiliently urging the doctor blade toward the wheel.

4. A fluid-applicator system as claimed in claim 1 and in which thecavity is provided with a fluid inlet and an overflow outlet, said bladebeing supported in a recess in said block connected to said inlet by apressure relief channel in said block, and closed-loop fluid supplymeans being connected to said inlet and said outlet to enablemultiple-position orientation of the system.

References Cited by the Examiner 593,341 5/1959 Italy.

CHARLES A. WILLMUTH, Primary Examiner.

25 L. G. MACHLIN, Assistant Examiner.

1. A FLUID-APPLICATOR SYSTEM HAVING, IN COMBINATION , A WHEEL FORRECEIVING FLUID ALONG THE PERIPHERAL SURFACE THEREOF MEANS FOR ROTATINGTHE WHEELS TO CONTACT SURFACESTO-BE-COATED BY THE FLUID, A BLOCK HOUSINGA FLUID-CONTAINING CAVITY THROUGH WHICH THE SUCCESSIVE PERIPHERALPORTIONS OF THE WHEEL MAY PASS DURING ROTATION OF THE WHEEL, AND ADOCTOR BLADE SUPPORTED BY THE BLOCK AND DISPOSED ADJACENT THE WHEELSUBSTANTIALLY AT THE END OF THE CAVITY FROM WHICH THE SUCCESSIVEPERIPHERAL SURFACE PORTIONS OF THE WHEEL EMERGE DURING THE SAIDROTATION,THE DOCTOR BLADE HAVING A CUTTER EDGE ORIENTED TO SLICE THEFLUID CARRIED THERETO TO A PREDETERMINED THICKNESS THE BLADE HAVING ADUCT PRECEDING THE CUTTER EDGE TO RECEIVE THE SLICED FLUID ND RE-DELIVERTHE SAME TO THE WHEEL PERIPHERAL SURFACE AHEAD OF THE CUTTER EDGE, SAIDBLADE BEING SUPPORTED ON SAID BLOCK FOR WHEEL SAID CUTTER EDGE HAVING APROJECPERIPHERY OF SAID WHEEL SAID CUTTER EDGE HAVING A PROJECTIONEXTENDING SUBSTANTIALLY TANGENTIAL TO SAID WHEEL AT SAID END OF THECAVITY AND EXTENDING REARWARDLY A PREDETERMINED DISTANCE INTO SAID DUCT,SAID DUCT HAVING A SUBSTANTIALLY CIRCULAR CROSS-SECTION WHICH EXTENDSFROM SAID EDGE PROGRESSIVELY FARTHER AWAY FROM THE PERIPHERY OF SAIDWHEEL AND THEN PROGRESSIVELY CLOSER TO THE PERIPHERY OF SAID WHEEL.